Solar Receiver for a Photo-Bioreactor

ABSTRACT

A solar receiver for a photo-bioreactor comprises a support having an interior, a vessel for supporting a biological culture, and at least one optical element. The optical element is arranged to receive light, and to direct the light to the interior of the support, to which the vessel is mounted.

PRIORITY

This application claims the benefit of priority to Irish patent application no. S2008/0128, filed Feb. 19, 2008, which is herein incorporated by reference.

This invention relates to a solar receiver for a photo-bioreactor. In particular, it relates to a device capable of supporting an environment of sustained optimal cultivation of a biological culture, and/or the biochemical substances produced thereby.

It is an object of the present invention to provide a solar receiver for a photo-bioreactor, which maintains the optimal conditions required to facilitate a bacterial culture performing a desired function, thereby increasing the efficiency of the photo-bioreactor.

According to a first aspect of the present invention there is provided a solar receiver for a photo-bioreactor comprising a support having an interior, a vessel for supporting a biological culture, and at least one optical element, wherein the at least one optical element is arranged to receive light, and to direct said light to the interior of the support, to which the vessel is mounted.

Preferably, the solar receiver comprises two optical elements. More preferably, a first optical element comprises a director, and a second optical element comprises a reflector.

Preferably, the director comprises a lens. Preferably, the lens is arranged to direct light to the reflector. Alternatively, the lens is arranged to direct light to the vessel.

Preferably, the reflector comprises a mirror. Preferably, the mirror is arranged to receive light from the lens, and to reflect said light to the vessel.

Preferably, the lens is a Fresnel-type lens, Most preferably, it is a non-imaging Fresnel-type lens adapted to direct light over at least part of the surface of the mirror.

Preferably, the lens and the mirror are respectively arranged such that the reflective surface of the mirror is located at the principal focal length of the lens.

Preferably, the lens is formed from a transparent plastics material. Although, it will be seen that any such material having the required optical properties may be used.

Preferably, the mirror is substantially convex in form.

Preferably, the solar receiver is arranged, in use, to allow sufficient light to be directed to the vessel to facilitate photosynthesis. More, preferably, the solar receiver is arranged, in use, to allow light to be directed to the vessel that is sufficient for optimal photosynthetic function of the biological culture supported therein.

Preferably, the vessel is adapted to allow a given range of wavelengths of light to pass to the interior of the vessel. The range of wavelengths is dependent on the accessory pigments of the bacterial culture supported within the vessel, and may be selected by one skilled in the art.

Preferably, the vessel is formed from a material that will allow a desired range of wavelengths of light to pass to the interior of the vessel.

Preferably, the material is transparent to the desired range of wavelengths of light required for photosynthesis.

Preferably, the vessel comprises an elongated length of tubing, having respective ends.

Preferably, each respective end of the tubing is adapted to engage with at least part of a photo-bioreactor.

Preferably, the tubing is arranged in a helical array.

Preferably, the tubing is arranged generally in the form of a conic helix.

Preferably, the reflector is arranged to direct light to the internal face of the helix. Further preferably, the reflector is arranged to receive light from the director.

Preferably, the support is adapted to allow a given range of wavelengths of light to pass to the interior of the vessel. The range of wavelengths is dependent on the accessory pigments of the bacterial culture supported within the vessel, and may be selected by one skilled in the art.

Preferably, the support is formed from a material that will allow a desired range of wavelengths of light to pass to the interior of the vessel.

Preferably, the support is transparent to the desired range of wavelengths of light required for photosynthesis.

Optionally, apertures are provided in the surface of the support to allow light to pass through the surface of the support.

Preferably, the support further comprises means for securing the vessel thereto.

Optionally, the support further comprises a base.

In a second aspect, there is provided an array of interconnected solar receivers according to the present invention, the vessel for each receiver being in fluid communication with a vessel for at least one other solar receiver.

Preferably, the array further comprises means for supplying each solar receiver of the array with nutrients, and means for removing a sample from each or some of the solar receivers.

Preferably, a common pipe is arranged to supply each of the solar receivers with nutrients. Further preferably, a second common pipe is arranged to remove a sample from said solar receivers.

An embodiment of the invention will now be described, with reference to the accompanying drawings in which:

FIG. 1 is a sectional view along the longitudinal axis of a solar receiver according to a preferred embodiment of the present invention;

FIG. 2 is a schematic diagram illustrating the solar receiver of FIG. 1 in use;

FIG. 3 is a schematic diagram illustrating a contiguous array of solar receivers of FIG. 2 in use; and

FIG. 4 is a schematic diagram illustrating a plan view of the contiguous array of solar receivers of FIG. 3 in use.

Referring now to FIG. 1, there is shown a solar receiver 10 for a photo-bioreactor (not shown). The solar receiver 10 comprises a support 14, a vessel for supporting a biological culture 12, a lens 20, and a mirror 22.

The support 14 comprises an upper section 16 and a lower section 16′. The lower section 16′ is generally frusto-conical in shape, having an otherwise open base and frustrum. The conical face of the lower section 16′ has a generally stepped form, wherein the circumference of each step is sequentially shorter in length than the step below, thereby forming a generally conic helix. The upper section 16 generally frusto-conical in shape having an open base and frustrum, and oriented in an opposite direction to the lower section 16′. The upper section 16 and the lower section 16′ are joined at the terminal edge defining the open frustrum of each section.

The upper and lower sections 16, 16′ of the support 14 may advantageously have an open configuration or a closed configuration. In the closed configuration, the support has a continuous surface. Accordingly, the support is preferably formed from a material that will allow a required range of wavelengths of light to pass to the interior of the vessel. In the closed configuration, the support has a semi-continuous surface, which may be achieved, for example, by providing apertures in the surface of the support, each of which allow sufficient light to pass to the interior of the vessel while being capable of supporting the vessel.

A generally circular base 18 is located at the terminal base edge of the lower section 16′.

The vessel for supporting a biological culture 12 comprises a generally elongate length of tubing. The tubing is generally circular in transverse cross-section. The tubing is wound sequentially along the steps defined on the conical face of the lower section 16′ of the support 14, resulting in the vessel forming a frustro-conical arrangement. At least part of the tubing can preferably be reversibly secured to the support by way of a plurality of fixings such as clips, more specifically a press fit clip (not shown).

The mirror 22 is generally curved in form having the reflective surface on the convex face of the mirror 22. The mirror is located within the lower section 16′ of the support 14, and is supported by a support 24, which is located on the base 18. The mirror 22 is oriented to receive light (broken arrows) from the lens 20, and reflect said light to the vessel 12.

The lens 20 is generally disc-shaped having concentric annular sections. Each of the annular sections of the lens 20 is arranged to refract and focus the rays of the light received at the lens, such that a single, concentrated beam of light is formed. Resultantly, the light furnished from the lens is, preferably, of a higher intensity than that light received at the lens, thereby maximising the flux uniformity and energy available from the light. The lens is located at the terminal upper edge of the upper section 16, and is arranged to receive solar light and to focus said light on the surface of the mirror 22.

FIG. 2 is a schematic diagram illustrating the solar receiver 10 in use at times when the sun is in different positions relative to the solar receiver 10. At position 1, which depicts the sun during, for example early morning or late evening periods, light from the sun is directed at an angle relative to the solar receiver 10. The conic helical arrangement of the vessel 12 allows for the maximal amount of light to be received by the outer face the vessel 12, during these periods. Moreover, the light received from this angle is directed by the lens 20 to the internal face of the vessel 12 via the mirror (not shown), thereby making maximal use of the low light conditions associated with this time of day. As the sun moves to position 2, which depicts the sun during, for example late morning or early evening periods, the light from the sun is directed both at an angle relative to the solar receiver 10 (lighter arrows) and from directly above the solar receiver 10 (darker arrows). The conic helical arrangement of the vessel 12 allows for the light from directly above the solar receiver 10 to be received by the outer face the vessel 12, during these periods. The light received from an angle can be directed by the lens 20 to the internal face of the vessel 12 via the mirror (not shown), thereby making maximal use of the differing light conditions associated with this time of day. At position 3, which depicts the sun during, for example midday, light from the sun is mainly directed from above to the solar receiver 10. The light received from directly above the solar receiver 10 is impeded from being directed to the vessel 12 via the mirror (not shown) by the position of the lens 20. Accordingly, the lens 20 acts as a physical impediment, and so limits the amount of light directed to the vessel 12, thereby protecting the vessel 12 from the intense light conditions associated with this time of day.

FIG. 3 is a schematic diagram illustrating a contiguous array of solar receivers 10 in use. The outer face of the vessel 12 of each solar receiver 10 can receive light directly from the sun (lighter arrows), which passes between the lenses 20 of neighbouring solar receivers 10. Similarly, diffuse ambient light (darker arrows) can pass between the lenses 20 of neighbouring solar receivers 10 to illuminate the outer surface of the vessel 12 of each solar receiver 10. Both light directly from the sun, and diffuse ambient light can be directed to the internal surface by the lens 20 to the internal face of the vessel 12 via the mirror (not shown).

FIG. 4 is a schematic diagram illustrating a plan view of a contiguous array of solar receivers 10. A common pipe 26 is located between each solar receiver 10, which delivers nutrients, or any such substance to each solar receiver 10, the direction of flow of which is depicted by the arrows projecting from the pipe 26. Similarly, a common pipe 26′ is located between each solar receiver 10, which removes samples, or any such substance from each solar receiver 10, the direction of flow of which is depicted by the arrows projecting from each solar receiver 10 to the pipe 26′.

Accordingly, the present invention provides a solar receiver for a photo-bioreactor, which maintains the optimal conditions required to facilitate a bacterial culture performing a desired function. In particular, the solar receiver facilitates the maximal use of available light in low-light conditions, and protects the bacterial culture within the photo-bioreactor in intense light conditions. Resultantly, the optimal light intensity is maintained throughout the photoperiod, facilitating increased efficiency of the photo-bioreactor.

As such, the present invention finds utility in the fields of chemical and biological engineering, in particular in the food, feed, pharmaceutical, biotechnology, and water-treatment industries.

The invention is not limited to the embodiments described herein but can be amended or modified without departing from the scope of the present invention. 

1. A solar receiver for a photo-bioreactor comprising a support having an interior, a vessel for supporting a biological culture, and at least one optical element, wherein the at least one optical element is arranged to receive light, and to direct said light to the interior of the support, to which the vessel is mounted.
 2. A solar receiver as claimed in claim 1 comprising two optical elements, a first optical element comprising a director, and a second optical element comprising a reflector.
 3. A solar receiver as claimed in claim 2 wherein the director comprises a lens arranged to direct light to the reflector.
 4. A solar receiver as claimed in claim 2 wherein the director comprises a lens arranged to direct light to the vessel.
 5. A solar receiver as claimed in claim 3 wherein the reflector comprises a mirror arranged to receive light from the lens, and to reflect said light to the vessel.
 6. A solar receiver according to claim 3 wherein the lens is a Fresnel-type lens.
 7. A solar receiver as claimed in claim 5 wherein the lens is a non-imaging Fresnel-type lens adapted to direct light over at least part of the surface of the mirror.
 8. A solar receiver as claimed in claim 5 wherein the lens and the mirror are respectively arranged such that the reflective surface of the mirror is located at the principal focal length of the lens.
 9. A solar receiver as claimed in claim 3 wherein the lens is formed from a transparent plastics material.
 10. A solar receiver as claimed in claim 5 wherein the mirror is substantially convex in form.
 11. A solar receiver as claimed in claim 1 wherein the solar receiver is arranged, in use, to allow sufficient light to be directed to the vessel to facilitate photosynthesis.
 12. A solar receiver as claimed in claim 1 wherein the solar receiver is arranged, in use, to allow light to be directed to the vessel that is sufficient for optimal photosynthetic function of the biological culture supported therein.
 13. A solar receiver as claimed in claim 1 wherein the vessel is adapted to allow a given range of wavelengths of light to pass to the interior of the vessel, the range of wavelengths being dependent on the accessory pigments of a bacterial culture supported within the vessel, and may be selected by one skilled in the art.
 14. A solar receiver as claimed in claim 1 wherein the vessel is formed from a material that allows a desired range of wavelengths of light to pass to the interior of the vessel.
 15. A solar receiver as claimed in claim 14 wherein the material is transparent to the desired range of wavelengths of light required for photosynthesis.
 16. A solar receiver as claimed in claim 2 wherein the vessel comprises an elongated length of tubing, having respective ends, each respective end of the tubing being adapted to engage with at least part of a photo-bioreactor.
 17. A solar receiver as claimed in claim 16 wherein the tubing is arranged in a helical array.
 18. A solar receiver as claimed in claim 17 wherein the tubing is arranged generally in the form of a conic helix.
 19. A solar receiver as claimed in claim 18 wherein the reflector is arranged to direct light to the internal face of the helix.
 20. A solar receiver as claimed in claim 1 wherein the support is adapted to allow a given range of wavelengths of light to pass to the interior of the vessel, the range of wavelengths being dependent on the accessory pigments of a bacterial culture supported within the vessel.
 21. A solar receiver as claimed in claim 1 wherein the support is formed from a material that will allow a desired range of wavelengths of light to pass to the interior of the vessel.
 22. A solar receiver as claimed in claim 1 wherein apertures are provided in the surface of the support to allow light to pass through the surface of the support.
 23. A solar receiver as claimed in claim 1 wherein the support further comprises means for securing the vessel thereto.
 24. An array comprising a plurality of interconnected solar receivers according to claim 1, the vessel for each receiver being in fluid communication with a vessel for at least one other solar receiver.
 25. An array as claimed in claim 24 wherein the array further comprises means for supplying each solar receiver of the array with nutrients, and means for removing a sample from each or some of the solar receivers.
 26. An array as claimed in claim 24 wherein a common pipe is arranged to supply each of the solar receivers with nutrients and wherein a second common pipe is arranged to remove a sample from said solar receivers. 